Roll stand for rolling different rolling stock that requires different roll separating forces

ABSTRACT

A rolling mill frame for the rolling of different rolled stock which requires different rolling forces and which has working rolls, back-up rolls, optionally a roll being device for the working rolls and optionally a device for adjusting and balancing the back-up rolls which has pairs of adjusting cylinders ( 3 ) between the roll stand ( 1 ) and the chucks ( 2 ) avoids large friction losses in that the adjusting cylinders ( 3 ) are each comprised of a telescoping cylinder ( 4 ) in which a first concentric ( 5 ) with a larger diameter for high rolling forces and a concentric cylinder ( 15 ) with smaller diameter for smaller rolling forces are provided.

[0001] The invention relates to a rolling mill stand for the rolling of different rolled stock which require different rolling forces and having a lower working roll and an upper working roll, back up rolls juxtaposed with the working rolls, optionally a roll bending device for the working rolls, and optionally devices for the setting and balancing of the back up rolls and pairs of adjusting cylinders between the roll stands and the chocks.

[0002] The hydraulic adjusting cylinders are used to generate the rolling force in the rolling mill. For the rolling mill a high product selectivity requires that the rolling mill be capable of having large rolling force differences between the individual products which are to be produced by a given rolling mill stand.

[0003] It is known to apply the different rolling forces with two adjusting cylinders for each rolling mill stand. In this case, however, the production of a lower rolling force may involve the same friction losses as a higher rolling force which can give rise to difficulties in control. A greater part of the higher friction losses may contribute to loading of the seals, the piston rod and the piston in a piston-and-cylinder unit.

[0004] To adjust the rolling force in a rolling mill stand, especially in a strip rolling mill stand for hot or cold rolling, it is known (DE 40 10 662 C2), in maintaining in a simple way the percentage of rolling force fluctuations in the course of rolling force control over an entire rolling force range, so as to be exceptionally small, to provide both adjusting cylinders with a respective cylinder housing and a cylinder pin, with a hat-shaped piston which is guided in a cylinder collar and in which the central piston surface formed by the internal hat button and the annular piston surface formed by the peripheral rim of the hat shaped piston are subjected to the pressure medium independently from one another or individually, or in common. This system, however, provides a plurality of friction surfaces which can complicate the control of the system.

[0005] The invention has as its object to reduce such friction losses and thereby enable a more precise control.

[0006] The object which has been set forth is achieved according to the invention in that setting cylinders each are comprised of a telescoping cylinder in which a first concentric cylinder is provided with a larger diameter for producing higher rolling forces and a second concentric cylinder is provided with a smaller diameter for producing smaller rolling forces. In this case friction forces arise only at the seals between the cylinder and the respective pistons. The friction losses are as a result smaller as a whole and thus allow a more precise control of the rolling force.

[0007] As a development of this basic concept it is proposed that the first larger cylinder with the greater diameter, form an outer annular pressurizable compartment whose pressure medium presses a larger piston ring against the cylinder bottom. The advantage is that the larger piston, during the actuation of the smaller piston, finds itself in a rest position and with smaller rolling forces, the friction at the larger piston can be completely eliminated so that friction only arises at the smaller piston which is substantially reduced.

[0008] In a refinement of the invention it is provided that the smaller piston of the second cylinder with the smaller diameter form within the larger piston a pressurizable compartment for the actuation of the smaller piston. This allows use of an advantage of the telescoping system, which is connected with a significant space saving.

[0009] A further feature of the invention provides that the pressure medium connection for the smaller cylinder extends through the cylinder wall and through the cylinder bottom of the larger cylinder. The advantage resides in a shorter medium line and in a separation of the pressure medium connections to two sides of the setting cylinder.

[0010] In a further refinement it is proposed that the pressure medium connection for the annular pressurizable compartment of the larger piston form a connection to the underside of the smaller piston. This also leads to a saving in the space required for the structure.

[0011] A short medium line also can result when the first or larger cylinder has a fluid medium connection opening in the region of the cylinder bottom. This can support the concept that the larger piston can remain in a rest position in which only the smaller piston is actuated for smaller rolling forces.

[0012] A further advantageous refinement has the first or larger cylinder so that it can be closed by means of a closure ring sealing the larger piston and defining an outer annular pressurizable compartment to which a fluid medium fitting for that outer compartment is connected. The closure ring can receive the sealing ring which seals against the larger piston and in part defines the annular pressurizable compartment.

[0013] In the sole FIGURE of the drawing a rolling mill stand has been shown for the rolling of different rolled stock which may require different rolling forces and which can receive upper and lower working rolls, not illustrated in detail, the back-up rolls juxtaposed with the working rolls, optionally a roll bending device for the working rolls and optionally devices for adjusting and balancing the back-up rolls. Pairs of adjusting cylinders 3 have been illustrated between the roll stand 1 and a chuck 2.

[0014] The adjusting cylinders 3 are each comprised of a telescoping cylinder 4 in each of the telescoping cylinders 4 there is a respective first larger cylinder 5 with an outwardly lying annular pressurizable compartment 5 a which is defined by a larger piston ring 5 b. The larger piston 5 d is sealed by means of a larger annular seal 6 in the cylinder housing 7.

[0015] Therebelow the cylinder housing 7 is closed by means of a closure ring 8 which also has annular seals 9 and 10 which seal against the larger diameter piston 5 d. Upon pressurization through the hydraulic fitting 11 opening into the annular pressurizable compartment 5 a, the larger diameter piston 5 d is displaced against the cylinder bottom 5 c as has been illustrated. The fluid pressure on the opposite side which would amount to a counterpressure, is drained via the pressure fitting 12. Within the first larger diameter piston 5 d, a pressurizable compartment 13 is formed which can be pressurized by the fitting 14. The pressure compartment 13 receives a second smaller diameter cylinder 15 which slides in the larger diameter piston 5 d and which encloses a second smaller diameter piston 15 a. The fluid pressure fitting 14 communicates with the pressurizable compartment 13 via a fluid medium passage 16 which runs through the upper region of the cylinder housing 7. The second smaller piston 15 a is sealed by corresponding sealed rings 17 and 18 whose diameter is smaller than the second smaller cylinder 15. A further sealing ring 19 is located on the smaller piston 15 a within the larger piston 5 d. The pressure medium fitting 14 feeds the hydraulic fluid through the cylinder wall 5 e and through the cylinder bottom 5 c.

[0016] In the left half of the illustration, the smaller piston 15 a is shown in its upper position and in the right half of the illustration in its lower position.

[0017] The fluid medium fitting 11 provides a communication 20 for the larger annular pressurizable compartment 5 a to the underside 15 b of the smaller piston 15 a.

[0018] The smaller piston 15 a of the second smaller cylinder 15 forms in its interior 21 the pressurizable compartment 13 for actuation of this smaller piston 15.

REFERENCE CHARACTER LIST

[0019]1 Roll mill stand

[0020]2 Chuck adjusting

[0021]3 Adjusting cylinder

[0022]4 Telescoping cylinder

[0023]5 First Larger cylinder

[0024]5 a Annular pressurizable compartment

[0025]5 b Larger piston ring

[0026]5 c Cylinder bottom

[0027]5 d Larger piston

[0028]5 e Cylinder wall

[0029]6 Annular seal

[0030]7 Cylinder housing

[0031]8 Closure ring

[0032]9 Annular seal

[0033]10 Annular seal

[0034]11 Pressure medium fitting

[0035]12 Pressure medium fitting

[0036]13 Pressurizable compartment

[0037]14 Pressure medium fitting

[0038]15 a Second smaller diameter cylinder

[0039]15 b Piston

[0040]16 Pressure medium passage

[0041]17 Sealing ring

[0042]18 Sealing ring

[0043]19 Sealing ring

[0044]20 Communication

[0045]21 Interior of the Larger piston 

1. A rolling mill stand for the rolling of different rolled stock which requires different rolling forces, are a lower working roll and an upper working roll, back-up rolls juxtaposed with the working rolls, optionally a roll bending device for the working rolls and optionally devices for adjusting and balancing the back-up rolls and pairs of adjusting cylinder between the rolling mill stand and the chucks, characterized in that the adjusting cylinders (3) are each comprised of a telescoping cylinder (4) in which a first concentric cylinder (5) with a larger diameter for higher rolling forces and a second concentric cylinder (15) for a smaller diameter for smaller rolling forces, are provided.
 2. The rolling mill stand according to claim 1 characterized in that the first larger cylinder (5) with the larger diameter forms an annular pressurizable compartment (5 a) whose pressure medium presses a larger piston ring (5 b) against the cylinder bottom (5 c).
 3. A rolling mill stand according to claim 1 characterized in that the smaller piston (15 a) of the second cylinder (15) with a smaller diameter forms in the interior (21) of the larger piston (5) a pressure chamber (13) for actuating the smaller piston (15 a).
 4. A rolling mill stand according to claim 3 characterized in that the pressure medium fitting (14) for the smaller piston (15 a) extends through the cylinder wall (5 e) and through the cylinder bottom 5 c of the larger cylinder (5).
 5. The rolling mill stand according to claim 1 characterized in that the pressure medium fitting (11) for the annular pressurizable compartment (5 a) of the larger piston (5 d) forms a communication (20) to the underside 15 b of the smaller piston 15 a.
 6. A rolling mill frame according to claim 1 characterized in that the first larger cylinder (5) has a pressure medium fitting (12) opening in the region of the cylinder bottom (5 c).
 7. The rolling mill stand according to claim 1 characterized in that the first larger cylinder (6) is closable by means of a closure ring (8) sealing relative to the larger piston (5 d) and to which the pressure medium fitting (11) for the outer annular compartment (5 a) is connected. 